Amino acid β-lyase enzyme inhibitors as deodorants

ABSTRACT

A deodorant composition comprising a body odor suppressing effective amount of an inhibitor of an amino acid  beta -lyase enzyme which catalyzes the formation of human body malodor in a dermatologically acceptable vehicle.

This application is a divisional of application Ser. No. 07/418,876,filed Oct. 10, 1989, now abandoned.

BACKGROUND OF THE INVENTION

The eccrine and apocrine sweat glands are the structures of the humanbody responsible for sweat. The apocrine glands become active at pubertyand produce an odorless proteinaceous secretion. Axillary bacteria acton the apocrine secretions to produce the pungent odor known as axillarymalodor. Prior to the current invention, the process by which bacteriaproduce malodor was unknown.

Current deodorants are generally of two types: odor maskers andgermicides. Despite the many disclosures in the art pertaining todeodorant compositions, current products are not sufficient to suppressodor in a significant proportion of the population, particularly duringperiods of "stress." Thus, there remains a need for deodorantcompositions and methods which are effective, safe and economical.

SUMMARY OF THE INVENTION

The present invention is a deodorant composition comprising a body odorsuppressing effective amount of an inhibitor of an amino acid β-lyaseenzyme in a dermatologically acceptable vehicle.

DETAILED DESCRIPTION OF THE INVENTION

The present invention includes novel compositions and a novel method ofsuppressing body odor by the topical application of a compositioncontaining at least one inhibitor of an enzyme, amino acid β-lyase,which catalyzes the formation of human body malodor. These uniquecompositions act to suppress the formation of axillary malodor byinhibiting an amino acid β-lyase enzyme that is found to create axillarymalodor within the bacterial cells. Such inhibitors include certainderivatized amino acids and hydroxylamines.

Deodorant compositions containing at least one of the inhibitingcompounds in a body odor suppressing effective concentration will serveto suppress axillary malodor when applied to the underarm. As shown bythe examples set forth below, these compositions significantly attenuatethe body odors formed in the axilla.

Axillary malodor is generated by certain skin bacteria in the presenceof apocrine secretion. Two strains of bacteria have been identifiedwhich produce axillary malodor when incubated with human apocrinesecretions. These are certain Staphylococcus species and severalCoryneform isolates. The conversion of apocrine precursor to axillarymalodor occurs within the bacterial cells. Even extracts of bacterialcells are capable of converting the precursor to the malodor compound inan enzymatic process. The enzyme which promotes this conversion has beendesignated as the malodor-forming enzyme and is an amino acid β-lyase.

Production of human axillary malodor can be assayed from these strainsof bacteria. One such assay is conducted by incubating bacteria (10⁹/ml) for 30 minutes at 37° C. in a phosphate buffer at pH 6.8 withapocrine secretions collected from human axilla. The volatile malodorcompound is then extracted into chloroform and smelled after spotting onfilter paper. A similar assay can be conducted using malodor-formingenzyme in place of the bacteria.

The malodor-forming enzyme has been found to be an amino acid β-lyasewhich acts in the axilla to cleave amino acids with the generalstructure COOH--CH(NH₂)--CH₂ --S--R where R is generally alkyl. Theresulting volatile sulfur products are responsible for the pungent smellcharacteristic of human axillary odor.

The malodor forming enzyme contains the cofactor pyridoxal phosphate.Pyridoxal phosphate dependent enzymes are known to be inhibited bycertain hydroxylamines and derivatized amino acids. The following groupsof compounds were found to be inhibitors of the malodor-forming enzyme.

Group 1: Hydroxylamine and other compounds of the formula H₂N--O--CH(R)COOH where R is hydrogen; phenyl; or C₁ -C₈ alkyl which isunsubstituted or substituted by a phenyl group, a hydroxy group, acarboxy group, a benzyloxy or benzyloxycarbonyl group, a halogen or anamino group.

Group 2: Amino acids containing a halogen at the β-carbon, such asβ-chloroalanine and trifluoroalanine, with the formula NH₂ --CH(--R)COOHwhere R is CR¹ R² R³ where R¹ is a halogen and R² and R³ are the same ordifferent and are hydrogen, chlorine, fluorine, iodine, bromine, aphenyl group, or C₁ -C₈ alkyl which is unsubstituted or substituted by aphenyl group, a hydroxy group, a carboxy group, a benzyloxy group, abenzyloxycarbonyl group or an amino group.

Group 3: α-Methyl amino acids of the formula NH₂ -C(CH₃)(COOH)--CH₂--S--R where R is hydrogen, phenyl, C₁ -C₈ alkyl which is unsubstitutedor substituted by a phenyl group, a hydroxy group, a carboxy group, abenzyloxy or benzyloxycarbonyl group, a halogen or an amino group.

Group 4: Cycloserine and related cyclic amino acids of the formula:##STR1## where R₁ and R₂ are hydrogen; phenyl; or C₁ -C₈ alkyl which isunsubstituted or substituted by a phenyl group, a hydroxy group, acarboxy group, a benzyloxy or benzyloxycarbonyl group or an amino group.

Group 5: Pyridoxal phosphate derivatives of the formula: ##STR2##wherein

R₂ is amino, halogen, saturated or unsaturated alkyl which isunsubstituted or substituted with an amino group, an oxo group, halogen,or a carboxylic group;

R₄ is amino, halogen, saturated or unsaturated alkyl which isunsubstituted or substituted with hydroxyl, an oxo group, a carboxylicgroup, halogen, or an amino group;

R₅ is hydrogen, unsaturated or saturated alkyl which is unsubstituted orsubstituted with a carboxylic group, a hydroxyl group, halogen, an oxogroup or a phosphate group; and

R₆ is hydrogen, halogen or an amino group.

The above compounds block enzymatic formation of axillary malodor andtherefore serve as deodorants.

Although deodorancy is the most important concern for the consumer ofunderarm products, many also choose a product with antiperspirantactivity. Current antiperspirants, which are aluminum salts, alsofunction as deodorants by virtue of their germicidal properties. Thus,if desired, the deodorants of the present invention can be employed withthe antiperspirant compounds well known in the art. In suchformulations, the inhibitors of the malodor forming enzyme of thepresent invention can be incorporated into an antiperspirant formulationwith the antiperspirant being employed in a perspiration reducingeffective concentration.

The antiperspirant component used in the present invention may be any ofthose which contain aluminum, either alone or in combination with othermaterials such as zirconium. Typical aluminum salts, although notall-inclusive, include:

Aluminum chlorohydrate;

Aluminum sesquichlorohydrate;

Aluminum dichlorohydrate;

Aluminum chlorohydrex PG or PEG;

Aluminum sesquichlorohydrex PG or PEG;

Aluminum dichlorohydrex PG or PEG;

Aluminum zirconium trichlorohydrate;

Aluminum zirconium tetrachlorohydrate;

Aluminum zirconium tetrachlorohydrex PG or PEG;

Aluminum zirconium pentachlorohydrate;

Aluminum zirconium octachlorohydrate;

Aluminum zirconium trichlorohydrex-gly;

Aluminum zirconium tetrachlorohydrex-gly;

Aluminum zirconium pentachlorohydrex-oily;

Aluminum zirconium octachlorohydrex-gly;

Aluminum zirconium chloride;

Aluminum zirconium sulfate;

Potassium aluminum sulfate;

Sodium aluminum chlorohydroxylacetate;

Aluminum bromohydrate.

In general the active antiperspirant component should be present in thesame amounts at which such materials are employed in prior artcompositions. As a general rule, the antiperspirant composition shouldcontain from about 5% to about 30%, preferably from about 10 to 25% ofthe active antiperspirant salt component.

In order to further illustrate the present invention and the advantagesthereof, the following specific examples are given. It is understoodthat these examples are intended only to be illustrative without servingto limit the scope of the present invention.

EXAMPLES Example 1 Evaluation of hydroxylamine and its derivatives

As a representative of hydroxylamine derivatives, aminooxyacetic acid(H₂ N--O--CH₂ --COOH) was investigated. Aminooxyacetic acid was shown toinhibit in vitro malodor formation in the assay described above atconcentrations from 0.1 to 10 μM in a pH 6.8 phosphate buffer.Inhibition was complete at concentrations over 3 μM. When tested for theability to block malodor formation when whole bacterial cells were usedin the malodor assay, the minimal concentration needed for completeinhibition was 100 μM. Aminooxyacetic acid at 0.11% by weight in waterat neutral pH was found to be efficacious when tested clinically fordeodorancy.

Further clinical trials were carried out to assess the deodorancyproperties of the Group 1 compound aminooxyacetic acid (AOA). AOA at1.1% by weight/volume at pH 7 in a vehicle of 50% propylene glycol/50%water outperformed triclosan, which was at 0.1% by weight/volume at selfpH in the same vehicle. Triclosan is a germicide employed as an activeingredient in certain current underarm deodorants. The combination ofAOA at 1.1% by weight/volume and triclosan at 0.1% by weight/volume atpH 7 in a vehicle of 50% propylene glycol/50% water outperformedtriclosan at 0.1% by weight volume at self pH in the same vehicle. AOAat 2.2% by weight also outperformed triclosan at 0.1% by weight in astick formulation. Finally, the combination of AOA at 1.1% by weight andthe antiperspirant aluminum chlorohydrate at 20% by weight in a vehicleof 50% propylene glycol/50% water outperformed aluminum chlorohydrate at20% by weight in the same vehicle.

Example 2 Evaluation of β-substituted amino acids.

Among the β-substituted amino acids, β-chloroalanine andtrifluoroalanine were tested for their ability to inhibit malodor invitro. Both inhibited activity; trifluoroalanine inhibited completely atconcentrations over 50 μM and β-chloroalanine inhibited completely atconcentrations over 10 μM. Both were tested in a pH 6.8 phosphatebuffer. Both compounds were effective in the inhibition of malodor inthe presence of whole bacterial cells at concentrations greater than 1mM. Trifluoroalanine was tested in a deodorancy, clinical trial andfound to be efficacious at 0.14% in water.

Example 3

Evaluation of α-methyl amino acid derivatives.

The α-methyl derivative of S-benzyl cysteine inhibits the formation ofmalodor in vitro. This compound also inhibits malodor formation in wholecells and by isolated malodor-forming enzyme at levels over 1 mM in a pH6.8 phosphate buffer.

Example 4 Evaluation of cycloserine and derivatives.

Cycloserine was tested in vitro against whole bacterial cells andmalodor-forming enzyme for its ability to inhibit malodor formation, andwas found to completely inhibit the formation of malodor in both systemsat levels over 1 mM in a pH 6.8 phosphate buffer.

Example 5 Evaluation of pyridoxal and its derivatives

Pyridoxal was tested in vitro against malodor-forming enzyme for itsability to inhibit the formation of malodor. It was effective ineliminating malodor at concentrations over 10 mM.

To prove that the inhibitors are suppressing malodor by enzymeinhibition rather than acting as germicides, several of the abovecompounds were tested for germicidal activity against axillary bacteria.Aminooxyacetic acid, trifluoroalanine, and L-cycloserine atconcentrations up to 0.1M had no inhibitory effect on the growth ofStaphylococcus cells in culture.

Formulations for Deodorant Use

The inhibitors of the present invention may be formulated forapplication to the skin employing any of the ingredients typically usedin deodorant and antiperspirant formulations. The concentration ofactive ingredient employed in topical applications should be consistentwith efficacy, economy and safety. The active inhibitors are efficaciouswithin concentrations of about 1 micromolar to about 2 molar. Thepreferred range is about 1-200 millimolar. This constitutes a weightpercent of about 0.01% to 3% as the preferred range of activeingredient.

If desired, the inhibitor of the present invention can also be employedin combination with an antiperspirant. In such case, the inhibitor ismerely added to the standard formulation for the antiperspirantcomposition in the same concentrations as set forth above.

Examples of formulations are given below:

    ______________________________________                                        1. Deodorant Stick         %                                                  ______________________________________                                        propylene glycol           78                                                 sodium stearate C-1        7.9                                                fragrance                  0.1                                                9 wt. % aminooxyacetic acid in water at neutral pH                                                       14                                                 ______________________________________                                    

Procedure: Mix propylene glycol and sodium stearate C-1 at roomtemperature and stir. Increase the temperature to about 70° C. andcontinue agitation to obtain a clear and uniform solution. Add theaminooxyacetic acid solution. Lower the temperature to 55° C. and addthe fragrance. Pour into molds and cool to room temperature.

    ______________________________________                                        2. Deodorant Roll-on Emulsion                                                                            %                                                  ______________________________________                                        hydrogenated palm oil glycerides and sodium                                                              3.0                                                cetyl sulfate                                                                 steareth-7                 1.0                                                octyldodecanol             4.0                                                glyceryl laurate           2.0                                                octyl palmitate            4.0                                                dimethicone                1.0                                                propylparaben              0.1                                                methylparaben              0.2                                                imidazolidinyl urea        0.3                                                glycerin                   5.0                                                allantoin                  0.5                                                PEG-35 lanolin             0.5                                                fragrance                  0.3                                                2 wt. % aminooxyacetic acid in water at neutral pH                                                       78.1                                               ______________________________________                                    

Procedure: Mix and stir the ingredients except the fragrance at 80° C.Decrease the temperature to 40° C. and add the fragrance. Decrease thetemperature to room temperature.

    ______________________________________                                        3. Aerosol Deodorant       %                                                  ______________________________________                                        zinc phenolsulfonate       1.7                                                quaternium 18 hectorite    1.0                                                dioctyl succinate          10.0                                               SDA 40 ethanol, anhydrous  20.0                                               fragrance                  0.1                                                10 wt. % aminooxyacetic acid in water at neutral pH                                                      10.0                                               propellent                 57.2                                               ______________________________________                                    

Procedure: Dissolve all ingredients in the alcohol, add the propellent,and cold or pressure fill.

    ______________________________________                                        4. Roll-on Antiperspirant and Deodorant                                                                  %                                                  ______________________________________                                        PPG-15 stearyl ether       4.0                                                steareth-21                0.6                                                steareth-2                 2.6                                                aluminum zirconium pentachlorohydrate, 10:1                                                              32.0                                               (a 25% solution)                                                              fragrance                  0.1                                                1.8 wt. % aminooxyacetic acid in water at neutral pH                                                     60.7                                               ______________________________________                                    

Mix all the ingredients except the fragrance at 70° C. with agitation.Add the fragrance at 45° C. Stir and cool to room temperature.

    ______________________________________                                        5. Aerosol Antiperspirant and Deodorant                                                               %                                                     ______________________________________                                        aminooxyacetic acid     1.0                                                   isopropyl myristate     13.4                                                  aluminum chlorohydrate  10.0                                                  quaternium-18 hectorite 0.8                                                   SDA 40 ethanol, anhydrous                                                                             0.8                                                   fragrance               0.1                                                   propellent              73.9                                                  ______________________________________                                    

Procedure: Mix the isopropyl myristate and quaternium-18 hectoritetogether for 30 min with an Eppenbach Homomixer. Add aluminumchlorohydrate and mix 15 min. Add the aminooxyacetic acid and SDA 40 andmix 10 min. Homogenize the suspension using a Manton-Gaulin homogenizerset at 6000 psi. Add fragrance and mix on a Hobart Mixer set at moderatespeed. Mix 10 min. Charge with propellent.

    ______________________________________                                        6. Stick Antiperspirant and Deodorant                                                                    %                                                  ______________________________________                                        aluminum chlorohydrate     16.0                                               SDA 40 ethanol, anhydrous  30.0                                               sorbitol, 70%              3.0                                                sodium stearate C-1        5.0                                                sodium ceteth-13 carboxylate                                                                             3.0                                                stearyl alcohol            1.0                                                cyclomethicone             15.0                                               fragrance                  0.1                                                4.1 wt. % aminooxyacetic acid in water at neutral pH                                                     26.9                                               ______________________________________                                    

Procedure: Mix the aluminum chlorohydrate, SDA 40 ethanol and theaminooxyacetic acid and heat to 65° C. Add sorbitol and then sodiumstearate C-1 and sodium ceteth-13 carboxylate, and mix until a completesolution is obtained. Add the remaining ingredients and mix for 5 min.Cool to 50° C. and add to containers.

While the invention has been described in terms of various embodiments,one skilled in the art will appreciate that various modifications,substitutions, omissions, and changes may be made without departing fromthe spirit thereof. Accordingly, it is intended that the scope of thepresent invention be limited solely by the scope of the followingclaims.

What is claimed is:
 1. A deodorant composition comprising a body odorsuppressing effective amount of an inhibitor of an amino acid β-lyaseenzyme containing the cofactor pyridoxal phosphate and which cleavesamino acids with the structure COOH--CH(NH₂)--CH₂ --S--R where R isalkyl, wherein the inhibitor is hydroxylamine or a compound of theformula

    H.sub.2 N--O--CH(R)COOH

where R is hydrogen; phenyl; or C₁ -C₈ alkyl which is unsubstituted orsubstituted by a phenyl group, a hydroxy group, a carboxy group, orbenzyloxy or benzyloxycarbonyl group, a halogen or an amino group, in adetermatologically acceptable vehicle.
 2. The composition of claim 1wherein the inhibitor is present at a concentration of at least 0.01% byweight.
 3. The composition of claim 1 wherein the inhibitor is presentat a concentration of about 1 micromolar to about 500 millimolar.
 4. Thecomposition of claim 1 wherein the concentration of inhibitor is about1-200 millimolar.
 5. The composition of claim 1, further comprising aperspiration reducing effective amount of an antiperspirant.
 6. A methodof suppressing body odor comprising the application to skin of thecomposition of claim
 1. 7. The composition of claim 1 wherein theinhibitor is aminooxyacetic acid.